Firefighters were dispatched to the blaze in the 2000 block of Caulfield Lane about 2:20 p.m.
By that time, flames had spread in the unit's kitchen but all the occupants had escaped, said Petaluma Fire Battalion Chief Jeff Holden.
It took firefighters about 20 minutes to put out the flames, Holden said. Holes in the roof were cut to release smoke that had built up in the fire.
A guinea pig and two gold fish inside the residence survived. The parrot died of smoke inhalation, Holden reported.
The cause of the fire appeared to be an unattended pot on the stove, Holden said.
In addition to structural damage, about $30,000 in belongings were lost in the fire.
The family has been relocated to a hotel and their animals have been taken in by relatives, Holden said.
— Brett Wilkison